This invention relates to the control of acarids. This invention further relates to compositions for controlling acarids, including mites, that can be applied directly to these organisms, their eggs or to areas, particularly plants, that are infested with these organisms.
Numerous phosphorus compounds have been disclosed as being effective control agents for acarids. For example, U.S. Pat. No. 2,754,242 teaches using alkyl bis(halophenyl)phosphinates to kill two-spotted spider mites. Many of these compounds are not practical for use as commercial insecticides, since they must be present at relatively high concentration levels (500 parts per million or more) to be effective. The in-use cost of these prior art materials may therefore be so high as to exclude them for large-scale applications.
It has now been found that certain tertiary bis(halophenyl)phosphines, phosphine oxides and phosphine sulfides are remarkably effective acaricides that can be employed at lower concentration levels than heretofore possible using many structurally related prior at materials, including those disclosed in the aforementined U.S. Pat. No. 2,754,242.